In preparing slabs and dimensional pieces of hard substances that form rigid building materials for transport, erection and attachment to structures, there are numerous approaches that are more or less effective. These hard substances may be, for example, slabs of slate, granite, limestone, marble, and other similar materials. The known approaches for preparing these materials generally require placement of a fastener or bolt of some sort within the rigid material. Because of the rigidity of these materials, however, there are substantial complications in penetrating the rigid material to form a hole in which to secure the fastener.
One approach is to place a vertically-canted hole in the slab and slide a bent bolt into the hole. The bent bolt protrudes from the vertically-canted hole to be perpendicular to the slab's surface. An epoxy holds the bent bolt within the canted hole. Limitations with this approach include the fact that the epoxy must hold the bolt throughout the life of the rigid material's on use the associated structure. To date, however, the epoxies that can hold the bent bolt in place have not been used for a sufficiently long period of time to verify that they will maintain their chemical composition and adhesive properties throughout the rigid material's life on the structure. Another problem with this technique is in the fact that it uses an epoxy that has constituent parts that must be mixed in precise proportions. Unless the epoxy parts are mixed in correct proportions, generally the epoxy will not properly secure the bent bolt in the vertically-canted hole.
It is also important to understand that the load bearing capacity of each one of these bent-bolt/epoxy assemblies is limited. For example, a multi-level building having a stone or granite curtain wall often uses as many as 200,000 of these bent-bolt/epoxy assemblies. Each one of these assemblies must be individual placed. With so many things that can go wrong with epoxy mixing, epoxy placement, and hole placement in a building requiring over 200,000 of these assemblies, a significant number of these assemblies could fail. Because these curtain walls are slabs of heavy granite, marble, or similar substances exposed to the public as the building's exterior, failure in even one of the 200,000 assemblies could injure a bystander. This poses an unacceptable risk associated with the use of these bent-bolt/epoxy assemblies.
Another known approach to this problem appears in U.S. Pat. No. 4,020,610 to Alexander (hereinafter Alexander). The method and system of Alexander prepare slabs of material such as granite for transportation and erection by using a cutting bit and a means for actuating the bit into the face of the slab. The means forms an arcuate slot that is widest at the bottom and centered outside the slab. The slot may be dove-tailed or an inverted T in configuration to receive the heads of a fastener by means of which the slab may be hoisted, transported, or finally secured as a curtain wall facing.
Significant problems exist with the approach of Alexander. These include the problem that the arcuate slot less than fully uses the material strength of the granite slab. This is because the holding strength of the fastener in the slot is primarily from the material above the fastener. Often this thickness is less than one-third the total thickness of the slab. Additionally, the arcuate slot is a complicated hole to form in the slab. This hole is difficult to form and, depending on the hardness or rigidity of the material, can be expensive to form in terms of both time and destruction of the cutting bit for making the arcuate slot.
Consequently, there is need for a method and system for securing an anchor to a rigid material that does not require or rely upon an epoxy to fasten the anchor into the rigid material.
There is a need for a method and system for securing an anchor to a rigid material that is simple and that does not consume an excessive amount of time in forming the penetration or hole and that does not consume cutting bits as rapidly as do known methods for making holes in which to secure the anchors.
There is a further need for a method and system for securing an anchor to a rigid material such as slate, granite, marble, glass, limestone, or other hard substances that permits the anchor to fully use the strength of the material to hold the anchor in place.